I have been using the FX Chrony for over a year now, with few, if any, real problems. The battery does run down quickly, but I use rechargeables and always have 3 fresh ones sitting in the charger. The minute I see the red light come on beside the green one I simply switch the batteries around. I have found that the inconsistencies increase if I continue to shoot after the red light warning comes on.
I find it so much easier to use than having to set up one of my two chronographs. For the first 3-4 months I would often test using both, but the results were so consistent between all three (never more than 1-2% off and generally consistent) that I no longer bother with that. I don’t get more dropped shots with the FX than I do with either of the other two optical chronographs.
Like elh0102 above, I simply find it easier and more consistent to hang the FX chrony off the barrel. Frankly they are light enough that I really don’t see a material difference in POI on most of my guns. If the POI does shift a little, the consistency in the new POI is still there.
I love the thing. For the price there is simply nothing that can touch it, and the ability to run out anytime and put around s down range through the radar beam is unsurpassed.
Chris